Dozens of Islamists demonstrated outside the synagogue last Friday and shouted, “Jews wait, the army of Mohammed is coming back,” and “We'll redo the battle of Khaybar” - a reference to the slaughter of Jews in what is now Saudi Arabia at the hands of Mohammed's army.

The interim government's Interior Ministry denounced the rally. “These people have no other motive than to attack the values of the republican regime based on the respect of freedom and belief, tolerance and peaceful co-existence,” officials said.

The government will “spare no effort to safeguard” civic rights and freedoms, they added.

Concern for a repeat of last Friday's threats is particularly high Friday as Muslim leaders give their weekly sermons, an event extremist preachers may take advantage of to incite against Jews.

Tunisia is home to approximately 1,600 Jews, down from 100,000 in the 1950s. The Jewish population is one of the largest in the Arab world. Most Tunisian Jews live on the southern island of Djerba.

The country's long-time leader, Zine El Abidine Ben Ali, was ousted last month after popular rallies for his removal. His ouster sparked protests across the Arab world that gained power last week with the successful ouster of Egyptian President Hosni Mubarak.